Copper foil provided with carrier, laminate, printed wiring board, electronic device and method for fabricating printed wiring board

ABSTRACT

Provided is a copper foil provided with a carrier in which the laser hole-opening properties of the ultrathin copper layer are good and which is suitable for producing a high-density integrated circuit substrate. A copper foil provided with a carrier having, in order, a carrier, an intermediate layer, and an ultrathin copper layer, wherein the specular gloss at 60° in an MD direction of the intermediate layer side surface of the ultrathin copper layer is 140 or less.

CROSS REFERENCE TO RELATED APPLICATION

The present invention is a divisional of U.S. patent application Ser.No. 15/015,551, filed on Feb. 4, 2016, the whole contents of which areincorporated herein by reference as if set forth explicitly herein.

TECHNICAL FIELD

The present invention relates to a copper foil provided with a carrier,a laminate, a printed wiring board, an electronic device and a methodfor fabricating a printed wiring board.

BACKGROUND ART

In general, a printed wiring board is fabricated through steps in whichan insulating substrate is adhered to a copper foil to make acopper-clad laminate and a conductive pattern is formed on the copperfoil surface by etching. High-density implementation of mountedcomponents and handling of signals at higher frequencies have beenprogressed along with the increase of the recent needs for smallerelectronic devices with a higher performance, and printed wiring boardsare needed to have a fine conductive pattern (fine pitch) and to dealwith high frequencies, for example.

Recently, while a copper foil having a thickness of 9 μm or less, oreven a thickness of 5 μm or less has been required to cope with a finepitch, such an ultrathin copper foil has a low mechanical strength, andis likely to tear or generate a wrinkle in fabricating a printed wiringboard. Accordingly, a copper foil provided with a carrier has beendeveloped in which an ultrathin copper layer is electrodeposited above athick metal foil, which is utilized for a carrier, with a peel layersandwiched therebetween. The surface of the ultrathin copper layer ispasted on an insulating substrate to heat and pressure-bond, andthereafter the carrier is peeled off and removed via the peel layer. Acircuit pattern is formed with a resist on the exposed ultrathin copperlayer and then a predetermined circuit is formed.

Here, in order to increase the integrated circuit density of a printedwiring board, a method is common in which a laser hole is formed and theinner layer and the outer layer are connected through the hole. Inaddition, because a method (MSAP: Modified-Semi-Additive-Process) inwhich a wiring circuit is formed on an ultrathin copper layer and theultrathin copper layer is then etching-removed with a sulfuricacid-hydrogen peroxide etchant is employed for a method for forming afine circuit in association with the popularization of a narrow pitch,the laser hole-opening properties of an ultrathin copper layer are animportant matter of concern to produce a high-density integrated circuitsubstrate. The laser hole-opening properties of an ultrathin copperlayer are involved in various conditions such as hole diameter precisionand laser output and hence significantly influence the design andproductivity of an integrated circuit.

In a common laser hole opening processing, the ultrathin copper layersurface is subjected to a blackening treatment or a fineirregularization treatment with a chemical solution in order to increasethe absorbability to a laser wavelength, and thereafter laser holeopening is performed. However, along with the popularization of highintegration, it has become common that the ultrathin copper layersurface is directly irradiated with a laser to open a laser hole withoutbeing subjected to the above treatments. The commonly used laser is acarbon dioxide laser and copper has a property to reflect the wavelengthregion of the laser. As a result, the laser hole-opening properties arenot improved without performing a treatment such as roughening of thesurface. As the technique, Patent Literature 1 discloses that acopper-clad laminate having good laser hole-opening properties can beprovided using a waved copper foil for the outer layer copper foil of acopper-clad laminate.

CITATION LIST Patent Literature

Patent Literature 1—Japanese Patent No. 3261119

SUMMARY OF INVENTION Technical Problem

However, roughening the ultrathin copper layer surface causes a problemof the deterioration of the fine circuit formability. Accordingly, it isthe object of the present invention to provide a copper foil providedwith a carrier in which the laser hole-opening properties of theultrathin copper layer are good and which is suitable for producing ahigh-density integrated circuit substrate.

Solution to Problem

As a result of diligent research to achieve the above object, thepresent inventors discovered that, by controlling the gloss of theintermediate layer side surface of the ultrathin copper layer in an MDdirection (longitudinal direction, rolling direction) or the gloss ofthe intermediate layer side surface of the ultrathin copper layer in aTD direction (width direction, traverse direction), the absorption to alaser wavelength by the ultrathin copper layer is improved, and as aresult a copper foil provided with a carrier in which the laserhole-opening properties of the ultrathin copper layer are good and whichis suitable for producing a high-density integrated circuit substratecan be provided.

The present invention, which was completed based on the above knowledge,is, in one aspect, a copper foil provided with a carrier having, inorder, a carrier, an intermediate layer, and an ultrathin copper layer,wherein the specular gloss at 60° in an MD direction of the intermediatelayer side surface of the ultrathin copper layer is 140 or less.

In an embodiment of the copper foil provided with a carrier according tothe present invention, the specular gloss at 60° in an MD direction ofthe intermediate layer side surface is 130 or less.

In another embodiment of the copper foil provided with a carrieraccording to the present invention, the specular gloss at 60° in an MDdirection of the intermediate layer side surface is 120 or less.

The present invention is, in another aspect, a copper foil provided witha carrier having, in order, a carrier, an intermediate layer, and anultrathin copper layer, wherein the specular gloss at 60° in a TDdirection of the intermediate layer side surface of the ultrathin copperlayer is 65 or less.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the specular gloss at 60° in a TDdirection of the intermediate layer side surface of the ultrathin copperlayer is 60 or less.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the specular gloss at 60° in a TDdirection of the intermediate layer side surface of the ultrathin copperlayer is 55 or less.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the average roughness Rz in an MDdirection of the intermediate layer side surface of the ultrathin copperlayer measured using a contact roughness meter is 1.5 μm or less.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the ten point average roughness Rzin an MD direction of the intermediate layer side surface of theultrathin copper layer measured using a contact roughness meter is 0.80μm or more.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the average roughness Rz in a TDdirection of the intermediate layer side surface of the ultrathin copperlayer measured using a contact roughness meter is 1.7 μm or less.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the specular gloss at 60° in an MDdirection of the intermediate layer side surface of the ultrathin copperlayer/the specular gloss at 60° in a TD direction of the intermediatelayer side surface of the ultrathin copper layer is 2.05 or less.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the average roughness Rz in an MDdirection of the intermediate layer side surface of the ultrathin copperlayer measured using a contact roughness meter/the average roughness Rzin a TD direction of the intermediate layer side surface of theultrathin copper layer measured using a contact roughness meter is 0.55or more.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the copper foil provided with acarrier has:

-   -   one or more layers selected from the group consisting of a        roughened layer, a heat resistant layer, an anti-corrosion        layer, a chromate-treated layer, and a silane coupling-treated        layer,    -   in the case that the copper foil provided with a carrier        according to the present invention has an ultrathin copper layer        on one side of the carrier, on at least one surface or both        surfaces on the ultrathin copper layer side and the carrier        side; or    -   in the case that the copper foil provided with a carrier        according to the present invention has an ultrathin copper layer        on both sides of the carrier, on one or both surface(s) on the        ultrathin copper layer side.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the roughened layer is a layerconsisting of a simple substance selected from the group consisting ofcopper, nickel, cobalt, phosphorous, tungsten, arsenic, molybdenum,chromium, and zinc, or an alloy containing one or more thereof.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the copper foil provided with acarrier includes a resin layer provided above one or more layersselected from the group consisting of the roughened layer, the heatresistant layer, an anti-corrosion layer, a chromate-treated layer, anda silane coupling-treated layer.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the copper foil provided with acarrier includes a resin layer provided above the ultrathin copperlayer.

In yet another embodiment of the copper foil provided with a carrieraccording to the present invention, the resin layer is a resin foradhesion and/or a resin in a semi-cured state.

The present invention is, in yet another aspect, a laminate fabricatedusing the copper foil provided with a carrier according to the presentinvention.

The present invention is, in yet another aspect, is a laminate includingthe copper foil provided with a carrier according to the presentinvention and a resin, wherein a part or all of an edge face of thecopper foil provided with a carrier is covered with the resin.

The present invention is, in yet another aspect, is a laminate, whereinone copper foil provided with a carrier according to the presentinvention is laminated from the carrier side or the ultrathin copperlayer side on the carrier side or the ultrathin copper layer side ofanother copper foil provided with a carrier according to the presentinvention.

The present invention is, in yet another aspect, a printed wiring boardfabricated using the copper foil provided with a carrier according tothe present invention.

The present invention is, in yet another aspect, an electronic devicefabricated using the printed wiring board according to the presentinvention.

In yet another aspect, the present invention is a method for fabricatinga printed wiring board including:

-   -   forming a copper-clad laminate by carrying out    -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate; and    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier; and    -   then forming a circuit by any of a semi-additive method, a        subtractive method, a partly additive method, and a modified        semi-additive method.

In yet another aspect, the present invention is a method for fabricatinga printed wiring board including: a step of forming a circuit on theultrathin copper layer side surface or the carrier side surface of thecopper foil provided with a carrier according to the present invention;

-   -   a step of forming a resin layer on the ultrathin copper layer        side surface or the carrier side surface of the copper foil        provided with a carrier so that the circuit is buried;    -   a step of forming a circuit on the resin layer;    -   a step of peeling the carrier or the ultrathin copper layer        after forming the circuit on the resin layer; and    -   a step of exposing the circuit buried in the resin layer that is        formed on the ultrathin copper layer side surface or the carrier        side surface by, after the carrier or the ultrathin copper layer        has been peeled off, removing the ultrathin copper layer or the        carrier.

The present invention is, in yet another aspect, a method forfabricating a printed wiring board including:

-   -   a step of laminating the copper foil provided with a carrier        according to the present invention on a resin substrate from the        carrier side;    -   a step of forming a circuit on the ultrathin copper layer side        surface of the copper foil provided with a carrier;    -   a step of forming a resin layer on the ultrathin copper layer        side surface of the copper foil provided with a carrier so that        the circuit is buried;    -   a step of forming a circuit on the resin layer;    -   a step of peeling the carrier after forming the circuit on the        resin layer; and    -   a step of exposing the circuit buried in the resin layer that is        formed on the ultrathin copper layer side surface by, after the        carrier has been peeled off, removing the ultrathin copper        layer.

The present invention is, in yet another aspect, is a method forfabricating a printed wiring board including:

-   -   a step of laminating the ultrathin copper layer side surface or        the carrier side surface of the copper foil provided with a        carrier according to the present invention and a resin        substrate;    -   a step of providing two layers of a resin layer and a circuit at        least one time on the ultrathin copper layer side surface or the        carrier side surface of the copper foil provided with a carrier        opposite to a side with the resin substrate laminated thereon;        and    -   a step of, after the two layers of the resin layer and the        circuit have been formed, peeling the carrier or the ultrathin        copper layer from the copper foil provided with a carrier.

The present invention is, in yet another aspect, is a method forfabricating a printed wiring board including:

-   -   a step of laminating the carrier side surface of the copper foil        provided with a carrier according to the present invention and a        resin substrate;    -   a step of providing two layers of a resin layer and a circuit at        least one time on the ultrathin copper layer side surface of the        copper foil provided with a carrier opposite to a side with the        resin substrate laminated thereon; and    -   a step of, after the two layers of the resin layer and the        circuit have been formed, peeling the carrier from the copper        foil provided with a carrier.

The present invention is, in yet another aspect, a method forfabricating a printed wiring board including:

-   -   a step of providing two layers of a resin layer and a circuit at        least one time on one side or both sides of the laminate        according to the present invention; and    -   a step of, after the two layers of the resin layer and the        circuit have been formed, peeling the carrier or the ultrathin        copper layer from the copper foil provided with a carrier        constituting the laminate.

Advantageous Effects of invention

According to the present invention, a copper foil provided with acarrier can be provided which the laser hole-opening properties of theultrathin copper layer are good and which is suitable for producing ahigh-density integrated circuit substrate.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are schematic views of a circuit board cross-sectionduring steps until circuit plating and resist removal according to aspecific example of the method for fabricating a printed wiring boardusing the copper foil provided with a carrier according to the presentinvention.

FIGS. 2D to 2F are schematic views of a circuit board cross-sectionduring steps from lamination of a resin and a second layer of a copperfoil provided with a carrier until laser hole opening according to aspecific example of the method for fabricating a printed wiring boardusing the copper foil provided with a carrier according to the presentinvention.

FIGS. 3G to 3I are schematic views of a circuit board cross-sectionduring steps from via fill formation until peeling of the first carrierlayer according to a specific example of the method for fabricating aprinted wiring board using the copper foil provided with a carrieraccording to the present invention.

FIGS. 4J to 4K are schematic views of a circuit board cross-sectionduring steps from flash etching until bump and copper pillar formationaccording to a specific example of the method for fabricating a printedwiring board using the copper foil provided with a carrier according tothe present invention.

FIG. 5 is a schematic view illustrating a method for polishing with anelectrolytic drum.

DESCRIPTION OF EMBODIMENTS Copper Foil Provided With Carrier

The copper foil provided with a carrier of the present invention, has,in order, the carrier, an intermediate layer and an ultrathin copperlayer. Methods for using a copper foil provided with a carrier itselfare well known to those skilled in the art. For example, the surface ofthe ultrathin copper layer is pasted on an insulating substrate such asa paper substrate phenolic resin, a paper substrate epoxy resin, asynthetic fiber fabric substrate epoxy resin, a glass cloth-papercomposite substrate epoxy resin, a glass cloth-glass non-woven compositesubstrate epoxy resin, and a glass cloth substrate epoxy resin, apolyester film and a polyimide film followed by heating andpressure-bonding; the carrier is then peeled off; the ultrathin copperlayer adhered to the insulating substrate is etched in an intendedconductive pattern; and eventually a printed wiring board can befabricated.

Carrier

The carrier that can be used in the present invention is typically ametal foil or a resin film, and provided in the form of, for example, acopper foil, a copper alloy foil, a nickel foil, a nickel alloy foil, aniron foil, an iron alloy foil, a stainless steel foil, an aluminum foil,an aluminum alloy film, an insulating resin film, a polyimide film, anLCD film, and a fluorine resin film.

The carrier that can be used in the present invention is typicallyprovided in the form of a rolled copper foil or an electrolytic copperfoil. Commonly, an electrolytic copper foil is fabricated byelectrolytic deposition of copper on a titanium or stainless steel drumfrom a copper sulfate bath, and a rolled copper foil is fabricated byrepeating plastic working and heat treatment with a mill roll. As thematerial for the copper foil, in addition to high-purity copper, such astough pitch copper (JIS H3100 alloy number C1100) and oxygen-free copper(JIS H3100 alloy number C1020 or JIS H3510 alloy number C1011), forexample, copper alloys can also be used, such as Sn-containing copper,Ag-containing copper, a copper alloy to which Cr, Zr, Mg, or the likehas been added, or a Colson copper alloy to which Ni, Si, and the likehas been added. Note that, when the term “copper foil” is used singlyherein, a copper alloy foil is also included therein.

Although the thickness of the carrier that can be used in the presentinvention is not especially limited, the carrier may be appropriatelyadjusted to a suitable thickness in view its role as a carrier, such as,for example, 5 μm or more. However, since production costs increase ifthe carrier is too thick, generally it is preferred that the thicknessis 35 μm or less. Therefore, the thickness of the carrier is typically 8to 70 μm, more typically 12 to 70 μm, and more typically 18 to 35 μm.From the perspective of reducing the raw material costs, the thicknessof the carrier is preferably small. Therefore, the thickness of thecarrier is typically 5 μm or more and 35 μm or less, preferably 5 μm ormore and 18 μm or less, preferably 5 μm or more and 12 μm or less,preferably 5 μm or more and 11 μm or less, and preferably 5 μm or moreand 10 μm or less. In the case that the thickness of the carrier issmall, a crease easily generates during conveying of the carrier in afoil. In order to prevent the generation of a crease, for example, it iseffective to smooth the conveying rolls in an apparatus for fabricatinga copper foil provided with a carrier and to reduce the distance betweenone conveying roll and the next one. In the case that a copper foilprovided with a carrier is used for a burying method (Embedded Process),which is one of methods for fabricating a printed wiring board, it isnecessary for the carrier to have a high stiffness. Accordingly, in thecase of being used for a burying method, the thickness of the carrier ispreferably 18 μm or more and 300 μm or less, preferably 25 μm or moreand 150 μm or less, preferably 35 μm or more and 100 μm or less, andeven more preferably 35 μm or more and 70 μm or less.

Further, a roughened layer may be provided on the surface opposite to asurface to be provided with the ultrathin copper layer of the carrier.The roughened layer may be provided using a known method, and may beprovided using the below-described roughening treatment. Providing aroughened layer on the surface opposite to a surface to be provided withthe ultrathin copper layer of the carrier has an advantage that whenlaminating the carrier on a support, such as a resin substrate, from thesurface side having the roughened layer, it is more difficult for thecarrier and the resin substrate to peel apart.

An example of fabrication conditions in the case that an electrolyticcopper foil is used as a carrier is shown below.

Electrolyte Composition

Copper: 90 to 110 g/L

Sulfuric acid: 90 to 110 g/L

Chlorine: 50 to 100 ppm

Leveling agent 1 (bis(3-sulfopropyl)disulfide): 10 to 30 ppm

Leveling agent 2 (amine compound): 10 to 30 ppm

An amine compound represented by the following chemical formula can beused for the above-described amine compound.

Note that the balance of a treatment solution used in electrolysis, asurface treatment, plating, or the like used in the present invention iswater unless otherwise noted.

wherein R1 and R2 are selected from the group consisting of ahydroxyalkyl group, an ether group, an aryl group, anaromatic-substituted alkyl group, an unsaturated hydrocarbon group, andan alkyl group.

Fabrication Conditions

Current density: 70 to 100 A/dm²

Electrolyte temperature: 50 to 60° C.

Electrolyte linear speed: 3 to 5 msec

Electrolysis time: 0.5 to 10 minutes

Intermediate Layer

An intermediate layer is provided on one side or both sides of thecarrier. Another layer may also be provided between the carrier and theintermediate layer. The intermediate layer used in the present inventionis not especially limited, as long as the configuration of the copperfoil provided with a carrier is such that the ultrathin copper layerdoes not easily peel from the carrier before the lamination step onto aninsulating substrate, and such that the ultrathin copper layer can peelfrom the carrier after the lamination step onto the insulatingsubstrate. For example, the intermediate layer of the copper foilprovided with a carrier according to the present invention may includeone or two or more selected from the group consisting of Cr, Ni, Co, Fe,Mo, Ti, W, P, Cu, Al, and Zn, alloys thereof, hydrates thereof, oxidesthereof, and organic substances. Further, a plurality of intermediatelayers may be provided.

In addition, for example, the intermediate layer can be configured fromthe carrier side from a single metal layer formed from one elementselected from the group of elements consisting of Cr, Ni, Co, Fe, Mo,Ti, W, P, Cu, Al, and Zn, or, configured by forming an alloy layerformed from one or two or more elements selected from the group ofelements consisting of Cr, Ni, Co, Fe, Mo, Ti, W, P, Cu, Al, and Zn, ora layer containing an organic substance and forming above that layer asingle metal layer or an alloy layer of one or two or more elementsselected from the group of elements consisting of Cr, Ni, Co, Fe, Mo,Ti, W, P, Cu, Al, and Zn or a layer of a hydrate or an oxide or anorganic substance thereof.

If the intermediate layer is provided on just one side, it is preferredto provide an anti-corrosion layer such as a Ni plating layer, on theopposite face of the carrier. In the case that the intermediate layer isprovided using a chromate treatment, a zinc chromate treatment, or aplating treatment, it is believed that a part of the metals attachedsuch as chromium and zinc may be in a state of a hydrate or an oxide.

Further, for example, the intermediate layer can be configured bylaminating a nickel, a nickel-phosphorus alloy, or a nickel-cobaltalloy, and a chromium, in that order, on the carrier. Since the adhesivestrength between nickel and copper is higher than the adhesive strengthbetween chromium and copper, when the ultrathin copper layer is peeled,the peeling occurs at the interface between the ultrathin copper layerand the chromium. Further, the nickel in the intermediate layer can beexpected to provide a barrier effect that prevents the diffusion of thecopper component from the carrier into the ultrathin copper layer. Theamount of nickel deposited in the intermediate layer is preferably 100μg/dm² or more and 40,000 μg/dm² or less, more preferably 100 μg/dm² ormore and 4,000 μg/dm² or less, more preferably 100 μg/dm² or more and2,500 μg/dm² or less, and more preferably 100 μg/dm² or more and lessthan 1,000 μg/dm². The amount of chromium deposited in the intermediatelayer is preferably 5 μg/dm² or more and 100 μg/dm² or less. If theintermediate layer is provided on just one side, it is preferred toprovide an anti-corrosion layer, such as a Ni plating layer, on theopposite face of the carrier.

The intermediate layer can be provided by performing for a carrier a wetplating such as an electroplating, an electroless plating, and animmersion plating, or a dry plating such as a sputtering, a CVD, and aPVD. In the case that the intermediate layer is provided using a wetplating with a resin film for a carrier, it is necessary to perform apretreatment such as an activation treatment for subjecting the carrierto a wet plating before formation of the intermediate layer. Theabove-described pretreatment which can be used may be any treatment aslong as it enables to perform a wet plating for a resin film, and knowntreatments can be used.

Ultrathin Copper Layer

The ultrathin copper layer is provided above the intermediate layer.Another layer may also be provided between the intermediate layer andthe ultrathin copper layer. The ultrathin copper layer can be formedthrough an electroplating utilizing an electrolytic bath of coppersulfate, copper pyrophosphate, copper sulfamate, copper cyanide, or thelike, and a copper sulfate bath is preferred because it is used for acommon electrolytic copper foil and enables to form a copper foil at ahigh current density. Although the thickness of the ultrathin copperlayer is not especially limited, the ultrathin copper layer is usuallythinner than the carrier, and may be, for example, 12 μm or less. Thethickness of the ultrathin copper layer is typically 0.01 to 12 μm, moretypically 0.05 to 12 μm, more typically 0.1 to 12 μm, more typically 1to 5 μm, even more typically 1.5 to 5 μm, and even more typically 2 to 5μm. Further, the ultrathin copper layer may be provided on both sides ofthe carrier.

Specular Gloss at 60° of Intermediate Layer Side Surface of UltrathinCopper Layer

In the copper foil provided with a carrier according to the presentinvention in one aspect, the specular gloss at 60° in an MD direction(hereinafter, also referred to as longitudinal direction or rollingdirection. MD direction: the direction perpendicular to the directionfor conveying a copper foil in an apparatus for fabricating anelectrolytic copper foil) of the intermediate layer side surface of theultrathin copper layer is controlled to be 140 or less. Further, in thecopper foil provided with a carrier according to the present inventionin another aspect, the specular gloss at 60° in a TD direction(hereinafter, also referred to as width direction or traverse direction.TD direction: the direction for conveying a copper foil in an apparatusfor fabricating an electrolytic copper foil) of the intermediate layerside surface of the ultrathin copper layer is controlled to be 65 orless.

A copper foil provided with a carrier is pasted on an insulatingsubstrate followed by heating and pressure-bonding; the carrier is thenpeeled off; and the ultrathin copper layer adhered to the insulatingsubstrate is etched in an intended conductive pattern to form a circuit.A printed wiring board is produced by making a substrate in amulti-layered structure in this way. Here, in order to increase theintegrated circuit density of such a printed wiring board, a laser holeis formed and the inner layer and the outer layer are connected throughthe hole. At this time, difficulty in opening a laser hole in theultrathin copper layer is of course problematic and both too large laserhole and too small laser hole cause various problems. Therefore, it isnecessary to form a laser hole with a moderate size. As seen from theabove, the laser hole-opening properties of the ultrathin copper layerare important properties which significantly influence the design andproductivity of an integrated circuit since they are involved in variousconditions such as hole diameter precision and laser output. In thepresent invention, it was discovered that controlling the specular glossat 60° in an MD direction (rolling direction) of the intermediate layerside surface of the ultrathin copper layer to be 140 or less, orcontrolling the specular gloss at 60° in a TD direction (traversedirection) of the intermediate layer side surface of the ultrathincopper layer to be 65 or less makes the laser hole-opening properties ofthe ultrathin copper layer good. If the specular gloss at 60° in an MDdirection of the intermediate layer side surface of the ultrathin copperlayer is more than 140, or the specular gloss at 60° in a TD directionof the intermediate layer side surface of the ultrathin copper layer ismore than 65, the specular gloss at 60° in an MD direction or a TDdirection of the intermediate layer side surface of the ultrathin copperlayer is too large and as a result the absorbability to a laser in holeopening processing is made too much, which causes a problem of too alarge hole.

The specular gloss at 60° in an MD direction of the intermediate layerside surface of the ultrathin copper layer is preferably 130 or less,more preferably 120 or less, and more preferably 110 or less. Furtherthe lower limit of the specular gloss at 60° in an MD direction of theintermediate layer side surface of the ultrathin copper layer may be,without being particularly limited, 0.1 or more, 0.5 or more, 1.0 ormore, 5.0 or more, or 10.0 or more.

The specular gloss at 60° in a TD direction of the intermediate layerside surface of the ultrathin copper layer is preferably 60 or less,more preferably 55 or less, and even more preferably 45 or less.Further, the lower limit of the specular gloss at 60° in a TD directionof the intermediate layer side surface of the ultrathin copper layer maybe, without being particularly limited, 0.1 or more, 0.5 or more, 1.0 ormore, 5.0 or more, or 10.0 or more.

Ten Point Average Roughness Rz of Intermediate Layer Side Surface ofUltrathin Copper Layer

In the copper foil provided with a carrier according to the presentinvention, the ten point average roughness Rz (JIS B0601 1982) in an MDdirection (rolling direction) of the intermediate layer side surface ofthe ultrathin copper layer measured using a contact roughness meter ispreferably 1.5 μm or less. This configuration enables to control theabsorbability to a laser in hole opening processing and as a result thelaser hole-opening properties of the ultrathin copper layer becomebetter. The ten point average roughness Rz of the intermediate layerside surface of the ultrathin copper layer is more preferably 1.4 μm orless, and even more preferably 1.3 μm or less. Further, the lower limitof the ten point average roughness Rz (JIS B0601 1982) in an MDdirection (rolling direction) of the intermediate layer side surface ofthe ultrathin copper layer may be, without being particularly limited,0.01 μm or more, 0.05 μm or more, or 0.1 μm or more. If the ten pointaverage roughness Rz (JIS B0601 1982) in an MD direction (rollingdirection) of the intermediate layer side surface of the ultrathincopper layer is 0.80 μm, preferably 0.85 μm or more, or preferably 0.90μm or more, the absorbability to a laser in hole opening processing canbe controlled to be better and as a result the laser hole-openingproperties of the ultrathin copper layer become better.

In the copper foil provided with a carrier according to the presentinvention, the ten point average roughness Rz (JIS B0601 1982) in a TDdirection (traverse direction) of the intermediate layer side surface ofthe ultrathin copper layer measured using a contact roughness meter ispreferably 1.7 μm or less. This configuration enables to control theabsorbability to a laser in hole opening processing and as a result thelaser hole-opening properties of the ultrathin copper layer becomebetter. The ten point average roughness Rz of the intermediate layerside surface of the ultrathin copper layer is more preferably 1.6 μm orless, and even more preferably 1.5 μm or less. Further, the lower limitof the ten point average roughness Rz (JIS B0601 1982) in a TD direction(traverse direction) of the intermediate layer side surface of theultrathin copper layer may be, without being particularly limited, 0.01μm or more, 0.05 μm or more, or 0.1 μm or more.

The above specular glosses at 60° and ten point average roughnesses Rzin an MD direction and a TD direction of the intermediate layer sidesurface of the ultrathin copper layer in the present invention can becontrolled in the following way. That is, on the intermediate layer sidesurface of a carrier on which an intermediate layer has been formed isformed a carrier with an electrolytic drum the ultrathin copperlayer-forming surface of which has been polished by using apredetermined polishing method. In the method for polishing anelectrolytic drum, the surface of an electrolytic drum is polished notonly in the rolling direction (MD direction) but also in the TDdirection. Specifically, as illustrated in FIG. 5, the polishing belt iscontacted to polish the electrolytic drum in the rolling direction (MDdirection) while rolling the electrolytic drum and simultaneously thepolishing belt is moved with oscillation also in the TD direction of theelectrolytic drum to thereby polish the electrolytic drum in the TDdirection as well. Here, a titanium drum can be used as the electrolyticdrum. In addition, as the polishing belt can be used a polishing beltusing a silicon carbide abrasive grain, an alumina abrasive grain, ortungsten carbide abrasive grain as the abrasive grain. The particle sizeof the abrasive grain is preferably a particle size of F 240 to F 1200or #320 to #4000 defined in JIS R6001 1998. The oscillation width of thepolishing belt in the TD direction is 0.01 to 5 mm, the movement of thepolishing belt in the traverse direction (stroke: the number of returnsof the center of the polishing belt to the same position in the TDdirection of the electrolytic drum surface within a certain time) is 50to 300 returns/min, the moving speed (carriage speed) of the polishingbelt in the TD direction is 20 to 100 cm/min, and the rotation speed ofthe electrolytic drum is 5 to 15 rpm. The width of the polishing beltcan be 50 to 300 mm.

By forming a carrier using an electrolytic drum the surface of which hasbeen polished in the MD direction and the TD direction in this way, thespecular glosses at 60° and ten point average roughnesses Rz in an MDdirection and a TD direction of the intermediate layer side surface ofthe ultrathin copper layer formed across the intermediate layer on thecarrier can be controlled.

Further, the above specular gloss at 60° in an MD direction/the abovespecular gloss at 60° in a TD direction is preferably 2.05 or less, morepreferably 2.00 or less, even more preferably 1.95 or less, and evenmore preferably 1.90 or less from the viewpoint of absorbing more laserlight.

Furthermore, the above ten point average roughness Rz in an MDdirection/the above ten point average roughness Rz in a TD direction ispreferably 0.55 or more, more preferably 0.60 or more, and even morepreferably 0.63 or more from the viewpoint of absorbing more laserlight.

Roughening Treatment and Other Surface Treatment

A roughened layer may be provided on the surface of the ultrathin copperlayer by performing a roughening treatment, for example, in order tomake the close adhesion properties to an insulating substrate good. Theroughening treatment can be carried out by forming roughened particleswith copper or a copper alloy, for example. The roughening treatment maybe a fine treatment. The roughened layer may be a layer consisting of asimple substance selected from the group consisting of copper, nickel,phosphorus, tungsten, arsenic, molybdenum, chromium, iron, vanadium,cobalt, and zinc, an alloy containing one or more thereof, or the like.Alternatively, after forming roughened particles with copper or a copperalloy, a roughening treatment can be carried out in which secondaryparticles or tertiary particles are further provided using a simplesubstance of nickel, cobalt, copper, or zinc, an alloy thereof, or thelike. Thereafter, a heat resistant layer or an anti-corrosion layer maybe formed with a simple substance of nickel, cobalt, copper, or zinc, analloy thereof, or the like, and further the surface may be subjected toa treatment such as a chromate treatment and a silane couplingtreatment. Alternatively, a heat resistant layer or an anti-corrosionlayer may be formed with a simple substance and/or an alloy and/or anoxide and/or a nitride and/or a silicide or the like of nickel, cobalt,copper, zinc, tin, molybdenum, tungsten, phosphorus, arsenic, chromium,vanadium, titanium, aluminum, gold, silver, a platinum group element,iron, or tantalum without performing any roughening treatment followedby further subjecting the surface to a treatment such as a chromatetreatment and a silane coupling treatment. That is, one or more layersselected from the group consisting of a heat resistant layer, ananti-corrosion layer, a chromate-treated layer, and a silanecoupling-treated layer may be formed on the surface of the roughenedlayer, or one or more layers selected from the group consisting of aheat resistant layer, an anti-corrosion layer, a chromate-treated layer,and a silane coupling-treated layer may be formed on the surface of theultrathin copper layer. The above-described roughened layer, heatresistant layer, anti-corrosion layer, chromate-treated layer, andsilane coupling-treated layer may be each formed in a plurality oflayers (e.g., two or more layers or three or more layers).

For example, copper-cobalt-nickel alloy plating as the rougheningtreatment can be performed by using electrolytic plating so that aternary alloy layer is formed with the amount deposited of copper,cobalt, and nickel being 15 to 40 mg/dm², 100 to 3,000 μg/dm², and 100to 1,500 μg/dm², respectively. If the amount of Co deposited is lessthan 100 μg/dm², the heat resistance is deteriorated and the etchingproperties may be worsened. If the amount of Co deposited is more than3,000 μg/dm², which is not preferred in the case that the influence ofmagnetic properties has to be considered, an etching spot may begenerated or the acid resistance and the chemical resistance may bedeteriorated. If the amount of Ni deposited is less than 100 μg/dm², theheat resistance may be worsened. On the other hand, if the amount of Nideposited is more than 1,500 μg/dm², the amount of etching residue maybe increased. The amount of Co deposited is preferably 1,000 to 2,500μg/dm², and the amount of nickel deposited is preferably 500 to 1,200μg/dm². Here, an etching spot means that, in etching with copperchloride, Co is left without being dissolved, and etching residue meansthat, in alkali-etching with ammonium chloride, Ni is left without beingdissolved.

An example of a common bath and plating conditions for forming such aternary copper-cobalt-nickel alloy plating are as follows.

Plating bath composition: Cu 10 to 20 g/L, Co 1 to 10 g/L, Ni 1 to 10g/L

pH: 1 to 4

Temperature: 30 to 50° C.

Current density Dk: 20 to 30 A/dm²

Plating time: 1 to 5 seconds

The chromate-treated layer refers to a layer treated with a solutioncontaining chromic anhydride, chromic acid, dichromic acid, a chromate,or a dichromate. The chromate-treated layer may contain an element suchas Co, Fe, Ni, Mo, Zn, Ta, Cu, Al, P, W, Sn, As, and Ti (any form isavailable such as a metal, an alloy, an oxide, a nitride, and asulfide). Specific examples of the chromate-treated layer include achromate-treated layer which has been treated with chromic anhydride oran aqueous solution of potassium dichromate and a chromate-treated layerwhich has been treated with a treatment solution containing chromicanhydride or potassium dichromate and zinc.

The silane coupling-treated layer may be formed using a known silanecoupling agent, and may be formed using a silane coupling agent such asan epoxy silane, an amino silane, a methacryloxy silane, a mercaptosilane, a vinyl silane, an imidazole silane, and a triazine silane orthe like. Two or more of these silane coupling agents may be used in amixture. Among them, the silane coupling-treated layer is preferablyformed using an amino silane coupling agent or an epoxy silane couplingagent.

In addition, the surface of the ultrathin copper layer, the roughenedlayer, the heat resistant layer, the anti-corrosion layer, the silanecoupling-treated layer, or the chromate-treated layer can be subjectedto a surface treatment described in International Publication No. WO2008/053878, Japanese Patent Laid-Open No. 2008-111169, Japanese PatentNo. 5024930, International Publication No. WO 2006/028207, JapanesePatent No. 4828427, International Publication No. WO 2006/134868,Japanese Patent No. 5046927, International Publication No. WO2007/105635, Japanese Patent No. 5180815, or Japanese Patent Laid-OpenNo. 2013-19056.

In this way, a copper foil provided with a carrier is fabricatedincluding a carrier, an intermediate layer laminated on the carrier, andan ultrathin copper layer laminated on the intermediate layer. Methodsfor using a copper foil provided with a carrier itself are well known tothose skilled in the art. For example, the surface of the ultrathincopper layer is pasted on an insulating substrate such as a papersubstrate phenolic resin, a paper substrate epoxy resin, a syntheticfiber fabric substrate epoxy resin, a glass cloth-paper compositesubstrate epoxy resin, a glass cloth-glass non-woven composite substrateepoxy resin, and a glass cloth substrate epoxy resin, a polyester filmand a polyimide film followed by heating and pressure-bonding; thecarrier is then peeled off to make a copper-clad laminate; the ultrathincopper layer adhered to the insulating substrate is etched in anintended conductive pattern; and eventually a printed wiring board canbe fabricated.

Further, the copper foil provided with a carrier including a carrier, anintermediate layer laminated on the carrier, and an ultrathin copperlayer laminated on the intermediate layer may be provided with aroughened layer above the ultrathin copper layer, and may be providedwith one or more layers selected from the group consisting of a heatresistant layer, an anti-corrosion layer, a chromate-treated layer, anda silane coupling-treated layer above the roughened layer.

Furthermore, the copper foil provided with a carrier may be providedwith a roughened layer above the ultrathin copper layer, and may beprovided with a heat resistant layer or anti-corrosion layer above theroughened layer, and may be provided with a chromate-treated layer abovethe heat resistant layer or anti-corrosion layer, and may be providedwith a silane coupling-treated layer above the chromate-treated layer.

Alternatively, the copper foil provided with a carrier may be providedwith a resin layer above the ultrathin copper layer, or above theroughened layer, or above the heat resistant layer, anti-corrosionlayer, or a chromate-treated layer, or a silane coupling-treated layer.The resin layer may be an insulating resin layer.

The above-described resin layer may be an adhesive, and may also be aninsulating resin layer in a semi-cured state (B stage state) foradhesion. This semi-cured state (B stage state) includes states in whichthere is no stickiness feeling even if the surface is touched with afinger, the insulating resin layer can be stacked and stored, and acuring reaction occurs when further subjected to a heating treatment.

Further, the above-described resin layer may include a thermosettingresin, or may be a thermoplastic resin. In addition, the above-describedresin layer may include a thermoplastic resin. The type of theabove-described resin layer is not especially limited. Examples ofpreferred resins can include one or more selected from the groupconsisting of epoxy resins, polyimide resins, polyfunctional cyanatecompounds, maleimide compounds, polymaleimide compounds, maleimideresins, aromatic maleimide resins, polyvinyl acetal resins, urethaneresins, polyether sulfone (also called polyether sulphone), polyethersulfone (also called polyether sulphone) resins, aromatic polyamideresins, aromatic polyamide resin polymers, rubber resins, polyamines,aromatic polyamines, polyamide-imide resins, rubber-modified epoxyresins, phenoxy resins, carboxyl group-modified acrylonitrile-butadieneresins, polyphenylene oxide, bismaleimide triazine resins, thermosettingpolyphenylene oxide resins, cyanate ester resins, carboxylic acidanhydrides, polybasic carboxylic acid anhydrides, linear polymers havinga crosslinkable functional group, polyphenylene ether resins,2,2-bis(4-cyanatophenyl)propane, phosphorus-containing phenol compounds,manganese naphthenate, 2,2-bis(4-glycidylphenyl)propane, polyphenyleneether-cyanate resins, siloxane-modified polyamide-imide resins, cyanoester resins, phosphazene resins, rubber-modified polyamide-imideresins, isoprene, hydrogenated polybutadiene, polyvinyl butyral,phenoxy, high-molecular-weight epoxys, aromatic polyamides,fluororesins, bisphenol, polyimide block copolymer resins, and cyanoester resins.

In addition, the above-described epoxy resin can be used without anyparticular problem as long as it has two or more epoxy groups in themolecule and can be used in electrical/electronic material applications.Moreover, an epoxy resin epoxied using a compound having two or moreglycidyl groups in the molecule is preferred. Further examples of epoxyresins that can be used include one or a mixture of two or more selectedfrom the group consisting of bisphenol A type epoxy resins, bisphenol Ftype epoxy resins, bisphenol S type epoxy resins, bisphenol AD typeepoxy resins, novolak type epoxy resins, cresol novolak type epoxyresins, alicyclic epoxy resins, brominated epoxy resins, phenol novolaktype epoxy resins, naphthalene type epoxy resins, brominated bisphenol Atype epoxy resins, ortho-cresol novolak type epoxy resins,rubber-modified bisphenol A type epoxy resins, glycidyl amine compoundssuch as glycidyl amine type epoxy resins, triglycidyl isocyanurate, andN,N-diglycidyl aniline, glycidyl ester compounds such as diglycidyltetrahydrophthalate, phosphorus-containing epoxy resins, biphenyl typeepoxy resins, biphenyl novolak type epoxy resins,tris(hydroxyphenyl)methane type epoxy resins, and tetraphenylethane typeepoxy resins. Also, a hydrogenated product or a halide of theabove-described epoxy resins may be used.

A known phosphorus-containing epoxy resin can be used for theabove-described phosphorus-containing epoxy resin. Further, it ispreferred that the above-described phosphorus-containing epoxy resin isan epoxy resin obtained as a derivative from, for example,9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide that includes two ormore epoxy groups in the molecule.

This resin layer may include known resins, resin curing agents,compounds, curing accelerators, dielectrics (any dielectric may be usedsuch as a dielectric containing an inorganic compound and/or an organiccompound and a dielectric containing a metal oxide), reaction catalysts,cross-linking agents, polymers, prepregs, skeletal materials, and thelike. Further, the resin layer may be formed using the substances(resins, resin curing agents, compounds, curing accelerators,dielectrics, reaction catalysts, cross-linking agents, polymers,prepregs, skeletal materials, and the like) and/or resin layer formationmethod and formation apparatus described in International PublicationNo. WO 2008/004399, International Publication No. WO 2008/053878,International Publication No. WO 2009/084533, Japanese Patent Laid-OpenNo. 1999-5828, Japanese Patent Laid-Open No. 1999-140281, JapanesePatent No. 3184485, International Publication No. WO 97/02728, JapanesePatent No. 3676375, Japanese Patent Laid-Open No. 2000-43188, JapanesePatent No. 3612594, Japanese Patent Laid-Open No. 2002-179772, JapanesePatent Laid-Open No. 2002-359444, Japanese Patent Laid-Open No.2003-304068, Japanese Patent No. 3992225, Japanese Patent Laid-Open No.2003-249739, Japanese Patent No. 4136509, Japanese Patent Laid-Open No.2004-82687, Japanese Patent No. 4025177, Japanese Patent Laid-Open No.2004-349654, Japanese Patent No. 4286060, Japanese Patent Laid-Open No.2005-262506, Japanese Patent No. 4570070, Japanese Patent Laid-Open No.2005-53218, Japanese Patent No. 3949676, Japanese Patent No. 4178415,International Publication No. WO 2004/005588, Japanese Patent Laid-OpenNo. 2006-257153, Japanese Patent Laid-Open No. 2007-326923, JapanesePatent Laid-Open No. 2008-111169, Japanese Patent No. 5024930,International Publication No. WO 2006/028207, Japanese Patent No.4828427, Japanese Patent Laid-Open No. 2009-67029, InternationalPublication No. WO 2006/134868, Japanese Patent No. 5046927, JapanesePatent Laid-Open No. 2009-173017, International Publication No. WO2007/105635, Japanese Patent No. 5180815, International Publication No.WO 2008/114858, International Publication No. WO 2009/008471, JapanesePatent Laid-Open No. 2011-14727, International Publication No. WO2009/001850, International Publication No. WO 2009/145179, InternationalPublication No. WO 2011/068157, Japanese Patent Laid-Open No.2013-19056.

The above-described resin is obtained in a B stage state by, forexample, dissolving in a solvent such as methyl ethyl ketone (MEK) andtoluene to produce a resin solution, coating the resin solution on theultrathin copper layer, or the heat resistant layer, anti-corrosionlayer, or the chromate film layer, or the silane coupling-treated layerby a roll coater method, for example, and then heating and drying asnecessary to remove the solvent. The drying can be carried out using,for example, a hot air drying furnace, at a drying temperature of 100 to250° C., and preferably 130 to 200° C.

The copper foil provided with a carrier including the above-describedresin layer (copper foil provided with a carrier provided with a resin)is used in a mode for forming a predetermined wiring pattern on theultrathin copper layer side surface by stacking the resin layer on thebase material, then heating and pressure-bonding the whole stack tothermally cure the resin layer, and then peeling the carrier to exposethe ultrathin copper layer to the surface (naturally the exposed portionis the surface on the intermediate layer side of the ultrathin copperlayer).

If this copper foil provided with a carrier provided with a resin isused, the number of sheets of prepreg material used when fabricating amultilayer printed wiring board can be reduced. Moreover, the thicknessof the resin layer can be set to a thickness that ensures interlayerinsulation, and a copper-clad laminate can be fabricated even withoutusing a prepreg material at all. Further, at this point, the smoothnessof the surface can be further improved by applying an insulating resinas an undercoat on the surface of the base material.

Further, not using a prepreg material has the economic advantages thatthe costs of the prepreg material can be saved, and the lamination stepcan be simplified. Moreover, there is also the advantage that thethickness of the multilayer printed wiring board to be fabricated isthinner by the thickness amount of the prepreg material, so that a verythin multilayer printed wiring board in which the thickness of one layeris 100 μm or less can be fabricated.

It is preferred that the thickness of this resin layer is 0.1 to 80 μm.If the thickness of the resin layer is thinner than 0.1 μm, the adhesivestrength can deteriorate, and it can become difficult to ensureinterlayer insulation between an inner layer material and the circuitwhen this copper foil provided with a carrier provided with a resin islaminated on a base material including an inner layer material withoutarranging a prepreg material therebetween.

On the other hand, if the resin layer thickness is thicker than 80 μm,it can be difficult to form a resin layer with a target thickness in onecoating step, so that extra material costs and steps are required, whichis economically disadvantageous. Further, since the resin layer formedis inferior in flexibility, a crack or the like is likely to begenerated in handling and an excessive resin flow may occur in heatingand pressure-bonding to the inner layer material resulting in difficultyin smooth lamination.

In addition, regarding another product form of this copper foil providedwith a carrier provided with a resin, it is also possible to cover thetop of the ultrathin copper layer, or the heat resistant layer, theanti-corrosion layer, or the chromate-treated layer, or the silanecoupling-treated layer with a resin layer, which is then semi-cured, andthereafter peel off the carrier to fabricate a copper foil provided witha resin without a carrier.

Further, a printed circuit board is completed by mounting electroniccomponents on the printed wiring board. In the present invention, a“printed wiring board” includes a printed wiring board with electroniccomponents mounted thereon in this way and a printed circuit board and aprinted substrate.

Furthermore, an electronic device may be produced using the printedwiring board, an electronic device may be produced using the printedcircuit board with electronic components mounted thereon, and anelectronic device may be produced using the printed substrate withelectronic components mounted thereon. Several examples of thefabrication steps of a printed wiring board using the copper foilprovided with a carrier according to the present invention will now bedescribed below.

An embodiment of the method for fabricating a printed wiring boardaccording to the present invention includes forming a copper-cladlaminate by carrying out a step of preparing the copper foil providedwith a carrier according to the present invention and an insulatingsubstrate, a step of laminating the copper foil provided with a carrierand the insulating substrate, and a step of, after the copper foilprovided with a carrier and the insulating substrate have been laminatedin such a manner that the ultrathin copper layer side of the copper foilfaces the insulating substrate, peeling the carrier of the copper foilprovided with a carrier, and then forming a circuit by any of asemi-additive method, a modified semi-additive method, a partly additivemethod, and a subtractive method. The insulating substrate can also beformed between the inner layer circuits.

In the present invention, semi-additive method refers to a method forforming a pattern by performing thin electroless plating on aninsulating substrate or a copper foil seed layer, and then forming aconductive pattern using electrolytic plating and etching.

Therefore, an embodiment of a method for fabricating a printed wiringboard according to the present invention using a semi-additive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of removing all of an ultrathin copper layer exposed by        the peeling of the carrier by a method such as plasma or etching        using a corrosive solution such as an acid;    -   a step of providing a through-hole and/or a blind via on a resin        exposed by removal of the ultrathin copper layer by etching;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of providing an electroless plating layer for a region        including the resin and the through-hole and/or blind via;    -   a step of providing a plating resist on the electroless plating        layer;    -   a step of exposing the plating resist and then removing the        plating resist in a region where a circuit is formed;    -   a step of providing an electrolytic plating layer on the region        where the circuit is formed from which the plating resist has        been removed;    -   a step of removing the plating resist; and    -   a step of removing the electroless plating layer in regions        other than where the circuit is formed by flash etching and the        like.

Another embodiment of a method for fabricating a printed wiring boardaccording to the present invention using a semi-additive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a through-hole and/or a blind via on an        ultrathin copper layer exposed by the peeling of the carrier and        the insulating rein substrate;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of removing all of the ultrathin copper layer exposed by        the peeling of the carrier by a method such as etching or plasma        using a corrosive solution such as an acid;    -   a step of providing an electroless plating layer for the region        including the resin exposed by removal of the ultrathin copper        layer by etching or the like and the through-hole and/or blind        via;    -   a step of providing a plating resist on the electroless plating        layer;    -   a step of exposing the plating resist and then removing the        plating resist in a region where a circuit is formed;    -   a step of providing an electrolytic plating layer on the region        where the circuit is formed from which the plating resist has        been removed;    -   a step of removing the plating resist; and    -   a step of removing the electroless plating layer in regions        other than where the circuit is formed by flash etching and the        like.

Another embodiment of a method for fabricating a printed wiring boardaccording to the present invention using a semi-additive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a through-hole and/or a blind via on an        ultrathin copper layer exposed by the peeling of the carrier and        the insulating rein substrate;    -   a step of removing all of the ultrathin copper layer exposed by        the peeling of the carrier by a method such as etching or plasma        using a corrosive solution such as an acid;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of providing an electroless plating layer for the region        including the resin exposed by removal of the ultrathin copper        layer by etching or the like and the through-hole and/or blind        via;    -   a step of providing a plating resist on the electroless plating        layer;    -   a step of exposing the plating resist and then removing the        plating resist in a region where a circuit is formed;    -   a step of providing an electrolytic plating layer on the region        where the circuit is formed from which the plating resist has        been removed;    -   a step of removing the plating resist; and    -   a step of removing the electroless plating layer in regions        other than where the circuit is formed by flash etching and the        like.

Another embodiment of a method for fabricating a printed wiring boardaccording to the present invention using a semi-additive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of removing all of the ultrathin copper layer exposed by        the peeling of the carrier by a method such as etching or plasma        using a corrosive solution such as an acid;    -   a step of providing an electroless plating layer for a surface        of the resin exposed by removal of the ultrathin copper layer by        etching;    -   a step of providing a plating resist on the electroless plating        layer;    -   a step of exposing the plating resist and then removing the        plating resist in a region where a circuit is formed;    -   a step of providing an electrolytic plating layer on the region        where the circuit is formed from which the plating resist has        been removed;    -   a step of removing the plating resist; and    -   a step of removing the electroless plating layer and ultrathin        copper layer in regions other than where the circuit is formed        by flash etching and the like.

In the present invention, modified semi-additive method refers to amethod for forming a circuit on an insulating layer by laminating ametal foil on an insulating layer, protecting a non-circuit formedportion with a plating resist, performing copper thickening of a circuitformed portion by electrolytic plating, then removing the resist, andremoving the metal foil at portions other than the circuit formedportion by (flash) etching.

Therefore, an embodiment of a method for fabricating a printed wiringboard according to the present invention using a modified semi-additivemethod includes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a through-hole and/or a blind via on an        ultrathin copper layer and the insulating substrate exposed by        the peeling of the carrier;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of providing an electroless plating layer for the region        including the through-hole and/or blind via;    -   a step of providing a plating resist on an ultrathin copper        layer surface exposed by the peeling of the carrier;    -   a step of, after providing the plating resist, forming a circuit        by electrolytic plating;    -   a step of removing the plating resist; and    -   a step of removing the ultrathin copper layer exposed by the        removal of the plating resist.

Another embodiment of a method for fabricating a printed wiring boardaccording to the present invention using a modified semi-additive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a plating resist on an ultrathin copper        layer exposed by the peeling of the carrier;    -   a step of exposing the plating resist and then removing the        plating resist in a region where a circuit is formed;    -   a step of providing an electrolytic plating layer on the region        where the circuit is formed from which the plating resist has        been removed;    -   a step of removing the plating resist; and    -   a step of removing the electroless plating layer and ultrathin        copper layer in regions other than where the circuit is formed        by flash etching and the like.

In the present invention, partly additive method refers to a method forfabricating a printed wiring board by providing a catalyst core on asubstrate that is provided with a conductive layer and in which holesfor through-holes and via holes have optionally been opened, forming aconductive circuit by etching, optionally providing a solder resist or aplating resist, and then performing thickening on the conductive circuitby an electroless plating treatment on the through-holes, via holes, andthe like.

Therefore, an embodiment of a method for fabricating a printed wiringboard according to the present invention using a partly additive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a through-hole and/or a blind via on an        ultrathin copper layer and the insulating substrate exposed by        the peeling of the carrier;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of providing a catalyst core for the region including the        through-hole and/or blind via;    -   a step of providing an etching resist on an ultrathin copper        layer surface exposed by the peeling of the carrier;    -   a step of exposing the etching resist to form a circuit pattern;    -   a step of forming a circuit by removing the ultrathin copper        layer and the catalyst core by a method such as plasma or        etching using a corrosive solution such as an acid;    -   a step of removing the etching resist;    -   a step of providing a solder resist or a plating resist on the        insulating substrate surface exposed by removing the ultrathin        copper layer and the catalyst core by a method such as plasma or        etching using a corrosive solution such as an acid; and    -   a step of providing an electroless plating layer in regions        where the solder resist or the plating resist is not provided.

In the present invention, subtractive method refers to a method forforming a conductive pattern by selectively removing an unnecessaryportion of copper foil on a copper-clad laminate by etching and thelike.

Therefore, an embodiment of a method for fabricating a printed wiringboard according to the present invention using a subtractive methodincludes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a through-hole and/or a blind via on an        ultrathin copper layer and the insulating substrate exposed by        the peeling of the carrier;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of providing an electroless plating layer for the region        including the through-hole and/or blind via;    -   a step of providing an electrolytic plating layer on a surface        of the electroless plating layer;    -   a step of providing an etching resist on a surface of the        electrolytic plating layer and/or the ultrathin copper layer;    -   a step of exposing the etching resist to form a circuit pattern;    -   a step of forming a circuit by removing the ultrathin copper        layer, the electroless plating layer, and the electrolytic        plating layer by a method such as plasma or etching using a        corrosive solution such as an acid; and    -   a step of removing the etching resist.

Another embodiment of a method for fabricating a printed wiring boardaccording to the present invention using a subtractive method includes:

-   -   a step of preparing the copper foil provided with a carrier        according to the present invention and an insulating substrate;    -   a step of laminating the copper foil provided with a carrier and        the insulating substrate;    -   a step of, after the copper foil provided with a carrier and the        insulating substrate have been laminated, peeling the carrier of        the copper foil provided with a carrier;    -   a step of providing a through-hole and/or a blind via on an        ultrathin copper layer and the insulating substrate exposed by        the peeling of the carrier;    -   a step of performing a desmearing treatment on a region        including the through-hole and/or blind via;    -   a step of providing an electroless plating layer for the region        including the through-hole and/or blind via;    -   a step of forming a mask on a surface of the electroless plating        layer;    -   a step of providing an electrolytic plating layer on a surface        of the electroless plating layer on which the mask is not        formed;    -   a step of providing an etching resist on a surface of the        electrolytic plating layer and/or the ultrathin copper layer;    -   a step of exposing the etching resist to form a circuit pattern;    -   a step of forming a circuit by removing the ultrathin copper        layer and the electroless plating layer by a method such as        plasma or etching using a corrosive solution such as an acid;        and    -   a step of removing the etching resist.

The step of providing a through-hole and/or a blind via and thesubsequent desmearing step do not have to be carried out.

Here, specific examples of the method for fabricating a printed wiringboard using the copper foil provided with a carrier according to thepresent invention will now be described with reference to the drawings.Further, although a copper foil provided with a carrier having anultrathin copper layer on which a roughened layer has been formed isdescribed here as an example, the present invention is not limited tothis. The below-described methods for fabricating a printed wiring boardcan be carried out in the same manner as using a copper foil providedwith a carrier having an ultrathin copper layer on which a roughenedlayer is not formed.

First, as illustrated in FIG. 1A, a copper foil provided with a carrier(first layer) having an ultrathin copper layer on which a roughenedlayer has been formed on the surface is prepared.

Next, as illustrated in FIG. 1B, a resist is coated on the roughenedlayer of the ultrathin copper layer, exposure and development is carriedout, and the resist is etched into a predetermined shape.

Next, as illustrated in FIG. 1C, a plating for a circuit is formed, andthen the circuit plating is formed in a predetermined shape by removingthe resist.

Next, as illustrated in FIG. 2D, a resin layer is laminated by providingan embedded resin on the ultrathin copper layer so as to cover thecircuit plating (so as to bury the circuit plating), and then a separatecopper foil provided with a carrier (second layer) is adhered from theultrathin copper layer side.

Next, as illustrated in FIG. 2E, the carrier is peeled from the secondlayer of the copper foil provided with a carrier.

Next, as illustrated in FIG. 2F, laser hole opening is performed on apredetermined position of the resin layer, and the circuit plating isexposed to form a blind via.

Next, as illustrated in FIG. 3G, copper is embedded in the blind via toform a via fill.

Next, as illustrated in FIG. 3H, a circuit plating is formed asillustrated in the above-described FIGS. 1-B and 1-C on the via fill.

Next, as illustrated in FIG. 3I, the carrier is peeled from the firstlayer of the copper foil provided with a carrier.

Next, as illustrated in FIG. 4J, the ultrathin copper layer on bothsurfaces is removed by flash etching to expose the surface of thecircuit plating in the resin layer.

Next, as illustrated in FIG. 4K, a bump is formed on the circuit platingin the resin layer, and a copper pillar is formed on that solder. Inthis manner, a printed wiring board using the copper foil provided witha carrier according to the present invention is produced.

Note that, in the above-described methods for fabricating a printedwiring board, replacing an “ultrathin copper layer” with a carrier andreplacing a “carrier” with an ultrathin copper layer, it is alsopossible to fabricate a printed wiring board by forming a circuit on thesurface on the carrier side of a copper foil provided with a carrier andthen burying the circuit in a resin.

For the above-described separate copper foil provided with a carrier(second layer), the copper foil provided with a carrier according to thepresent invention can be used, a conventional copper foil provided witha carrier may be used, or a normal copper foil may be used. Further, acircuit may be formed in one layer or a plurality of layers on thecircuit of the second layer illustrated in FIG. 3H. These circuits canbe formed by any of a semi-additive method, a subtractive method, apartly additive method, and a modified semi-additive method.

According to such a printed wiring board fabrication method, since thecircuit plating is buried in the resin layer, during removal of theultrathin copper layer by flash etching like that illustrated in FIG.4J, for example, the circuit plating is protected by the resin layer, sothat the shape of the circuit plating is retained, which facilitatesformation of a fine circuit. In addition, since the circuit plating isprotected by the resin layer, migration resistance is improved, andcircuit wiring conduction can be properly suppressed. Consequently, theformation of a fine circuit is easy. Still further, when the ultrathincopper layer has been removed by flash etching as illustrated in FIGS.4J and 4K, since the exposed face of the circuit plating has a shapethat is recessed from the resin layer, the bumps tend to be formed onthat circuit plating and copper pillars tend to be formed above thebumps even more easily, so that production efficiency is improved.

Moreover, a known resin and prepreg can be used for the buried resin.For example, a BT (bismaleimide triazine) resin, a glass cloth prepregimpregnated with a BT resin, an ABF film or ABF manufactured byAjinomoto Fine-Techno Co., Inc., can be used. Further, the resin layerand/or resin and/or prepreg described in the present specification canbe used for the above-described buried resin.

In addition, the above-described copper foil provided with a carrierused for the first layer may have a substrate or a resin layer on thesurface of the copper foil provided with a carrier. By having such asubstrate or resin layer, the copper foil provided with a carrier usedfor the first layer is supported, so that wrinkles are less likely toform. Consequently, there is the advantage that productivity isimproved. Moreover, any substrate or resin layer may be used for thissubstrate or resin layer, as long as the substrate or resin layer has aneffect of supporting the above-described copper foil provided with acarrier used for the first layer. For example, the carrier, the prepreg,and the resin layer described in the specification of the presentapplication, or a known carrier, prepreg, resin layer, metal sheet,metal foil, sheet of an inorganic compound, foil of an inorganiccompound, sheet of an organic compound, or foil of an organic compoundcan be used as the above-described substrate or resin layer.

Further, the method for fabricating a printed wiring board according tothe present invention may be a method for fabricating a printed wiringboard including: a step of laminating the ultrathin copper layer sidesurface or the carrier side surface of the copper foil provided with acarrier according to the present invention and a resin substrate; a stepof providing two layers of a resin layer and a circuit at least one timeon the surface of the copper foil provided with a carrier opposite tothe ultrathin copper layer side surface or the carrier side surface withthe resin substrate laminated thereon; and a step of, after the twolayers of the resin layer and the circuit have been formed, peeling thecarrier or the ultrathin copper layer from the copper foil provided witha carrier (coreless method). In a specific example of the corelessmethod, first, the ultrathin copper layer side surface or the carrierside surface of the copper foil provided with a carrier according to thepresent invention and a resin substrate are laminated to fabricate alaminate. Subsequently, a resin layer is formed on the surface of thecopper foil provided with a carrier opposite to the ultrathin copperlayer side surface or the carrier side surface with the resin substratelaminated thereon. A separate copper foil provided with a carrier may belaminated from the carrier side or the ultrathin copper layer side onthe resin layer formed on the carrier side surface or the ultrathincopper layer side surface. Further, a laminate having a configuration inwhich a copper foil provided with a carrier is laminated on bothsurfaces of the resin substrate or resin or prepreg, which is positionedat the center, in an order of a carrier/an intermediate layer/anultrathin copper layer or an ultrathin copper layer/an intermediatelayer/a carrier, or a laminate having a configuration in which “acarrier/an intermediate layer/an ultrathin copper layer/a resinsubstrate or resin or prepreg/a carrier/an intermediate layer/anultrathin copper layer” are laminated in this order may be used for theabove-described method for fabricating a printed wiring board (corelessmethod). In addition, on the exposed surface of the ultrathin copperlayer or the carrier at both ends of the laminate, a separate resinlayer may be provided to form a circuit by further providing a copperlayer or metal layer and thereafter processing the copper layer or metallayer. A separate resin layer may be further provided on the circuit soas to bury the circuit. Further, such formation of a circuit and a resinlayer may be carried out one or more times (build-up method). And forthe laminate formed in this way (hereinafter, also referred to aslaminate B), a coreless substrate can be produced by peeling theultrathin copper layer or the carrier of each copper foil provided witha carrier from the carrier or the ultrathin copper layer. For producingthe above-described coreless substrate, two copper foils provided with acarrier can be used to produce a laminate having a configuration of anultrathin copper layer/an intermediate layer/a carrier/a carrier/anintermediate layer/an ultrathin copper layer, a laminate having aconfiguration of a carrier/an intermediate layer/an ultrathin copperlayer/an ultrathin copper layer/an intermediate layer/a carrier, or alaminate having a configuration of a carrier/an intermediate layer/anultrathin copper layer/a carrier/an intermediate layer/an ultrathincopper layer as described below to use the laminate as the center. Acoreless substrate can be produced by providing two layers of a resinlayer and a circuit one or more times on surfaces of the ultrathincopper layers or the carriers on both sides of these laminates(hereinafter, also referred to as laminate A), and, after the two layersof the resin layer and the circuit have been provided, peeling theultrathin copper layer or the carrier of each copper foil provided witha carrier from the carrier or the ultrathin copper layer. Theabove-described laminate may have another layer on the surface of theultrathin copper layer, on the surface of the carrier, between thecarriers, between the ultrathin copper layers, or between the ultrathincopper layer and the carrier. The other layer may be a resin substrateor a resin layer. In the present specification, in the case that anultrathin copper layer, a carrier, or a laminate has another layer onthe ultrathin copper layer surface, the carrier surface, or the laminatesurface, “surface of an ultrathin copper layer,” “ultrathin copper layerside surface,” “ultrathin copper layer surface,” “surface of a carrier,”“carrier side surface,” “carrier surface,” “surface of a laminate,” and“laminate surface” are a concept also including the surface (outermostsurface) of the another layer. Further, the laminate preferably has aconfiguration of an ultrathin copper layer/an intermediate layer/acarrier/a carrier/an intermediate layer/an ultrathin copper layer. Thisis because, when a coreless substrate is produced using the laminate,the ultrathin copper layer is disposed on the coreless substrate side,which facilitates formation of a circuit on the coreless substrate usinga modified semi-additive method. In addition, the reason is that, sincethe thickness of the ultrathin copper layer is small, it is easy toremove the ultrathin copper layer, which facilitates formation of acircuit on the coreless substrate using a semi-additive method afterremoving the ultrathin copper layer.

In the present specification, “laminate” which is not particularlystated as “laminate A” or “laminate B” indicates a laminate including atleast a laminate A and a laminate B.

In the above-described method for fabricating a coreless substrate, whenfabricating a printed wiring board using a build-up method, by coveringa part or all of the edge face of the copper foil provided with acarrier or the above-described laminate (including laminate A) with aresin, the permeation of a chemical solution into the intermediate layeror a space between one copper foil provided with a carrier and anothercopper foil provided with a carrier constituting the laminate can besuppressed, and the separation of the ultrathin copper layer and thecarrier and the corrosion of the copper foil provided with a carrier dueto the permeation of a chemical solution can be prevented and yield canbe improved. As the “resin covering a part or all of the edge face ofthe copper foil provided with a carrier” or the “resin covering a partor all of the edge face of the laminate” used here, a resin which can beused for the resin layer or a known resin can be used. Further, in theabove-described method for fabricating a coreless substrate, when thecopper foil provided with a carrier or the laminate is viewed in aplane, at least a part of the periphery of a laminated part of thecopper foil provided with a carrier or the laminate (a laminated part ofa carrier and an ultrathin copper layer, or a laminated part of onecopper foil provided with a carrier and another copper foil providedwith a carrier) may be covered with a resin or a prepreg. Further, alaminate (laminate A) formed by using the above-described method forfabricating a coreless substrate may have a configuration in which apair of copper foils provided with a carrier are contacted with eachother in a separable manner. Furthermore, when the copper foil providedwith a carrier is viewed in a plane, all of the periphery of a laminatedpart or the whole surface of a laminated part of the copper foilprovided with a carrier or the laminate (a laminated part of a carrierand an ultrathin copper layer, or a laminated part of one copper foilprovided with a carrier and another copper foil provided with a carrier)may be covered with a resin or a prepreg. When the copper foil providedwith a carrier is viewed in a plane, a resin or a prepreg is preferablylarger than the copper foil provided with a carrier or the laminate orthe laminated part of the laminate, and it is preferred to laminate theresin or prepreg on both sides of the copper foil provided with acarrier or laminate to make a laminate having a configuration in whichthe copper foil provided with a carrier or laminate is enveloped(covered) with the resin or prepreg. By adopting such a configuration,when the copper foil provided with a carrier or the laminate is viewedin a plane, the laminated part of the copper foil provided with acarrier or the laminate is covered with a resin or a prepreg, and it canbe prevented for another member to touch from the lateral direction ofthis part, that is, the transverse direction against the laminationdirection, and as a result, the peeling of the carrier and the ultrathincopper layer or copper foils provided with a carrier can be less likelyto occur in handling. Further, by covering the periphery of a laminatedpart of the copper foil provided with a carrier or the laminate with aresin or a prepreg so as not to expose it, the above-describedpermeation of a chemical solution into the interface of this laminatedpart in a chemical solution treatment step can be prevented, and thecorrosion and erosion of the copper foil provided with a carrier can beprevented. It should be noted that, when one copper foil provided with acarrier is separated from a pair of copper foils provided with a carrierof the laminate or when the carrier and the copper foil (ultrathincopper layer) of the copper foil provided with a carrier are separatedfrom each other, the laminated part of the copper foil provided with acarrier or the laminate (the laminated part of the carrier and theultrathin copper layer, or the laminated part of one copper foilprovided with a carrier and another copper foil provided with a carrier)covered with a resin or a prepreg needs to be removed by cutting or thelike.

The copper foil provided with a carrier according to the presentinvention may be laminated from the carrier side or the ultrathin copperlayer side on the carrier side or the ultrathin copper layer side ofanother copper foil provided with a carrier according to the presentinvention to constitute a laminate. Further, the laminate may be alaminate obtained by directly laminating as necessary via an adhesivethe carrier side surface or the ultrathin copper layer side surface ofthe one copper foil provided with a carrier and the carrier side surfaceor the ultrathin copper layer side surface of the another copper foilprovided with a carrier. Furthermore, the carrier or the ultrathincopper layer of the one copper foil provided with a carrier and thecarrier or the ultrathin copper layer of the another copper foilprovided with a carrier may be bonded together. Here, in the case thatthe carrier or the ultrathin copper layer has a surface-treated layer,the “bonding” includes a mode in which they are bonded together via thesurface-treated layer. In addition, a part or all of the edge face ofthe laminate may be covered with a resin.

Lamination of carriers can be carried out by simply stacking or, forexample, by using the following methods.

-   -   (a) metallurgical bonding method: fusion welding (arc welding,        TIG (tungsten/inert gas) welding, MIG (metal/inert gas) welding,        resistance welding, seam welding, spot welding), pressure        welding (ultrasonic welding, friction stir welding), and brazing        and soldering;    -   (b) mechanical bonding method: caulking, bonding with a rivet        (bonding with a self-piercing rivet and bonding with a rivet),        and a stitcher; and    -   (c) physical bonding method: an adhesive and a (double-sided)        adhesive tape.

By bonding a part or all of one carrier and a part or all of the othercarrier together using the above bonding method, a laminate having aconfiguration in which one carrier and the other carrier are laminatedand contacted with each other in a separable manner can be fabricated.If one carrier and the other carrier are laminated in a state that onecarrier and the other carrier are weakly bonded together, one carrierand the other carrier are separable from each other even withoutremoving the bonding part of one carrier and the other carrier. On theother hand, if one carrier and the other carrier are strongly bondedtogether, one carrier and the other carrier can be separated from eachother by removing the part to which one carrier and the other carrierbonds by cutting, chemical polishing (e.g., etching), mechanicalpolishing, or the like.

In addition, a printed wiring board without a core can be produced byperforming a step of providing two layers of a resin layer and a circuitat least one time on the laminate configured in this way, and a step of,after the two layers of the resin layer and the circuit have been formedat least one time, peeling the ultrathin copper layer or the carrierfrom the copper foil provided with a carrier of the laminate. Further,two layers of a resin layer and a circuit may be provided on the surfaceof one side or both sides of the laminate.

The resin substrate, resin layer, resin, or prepreg to be used for theabove-described laminate may be the resin layer described herein, andmay include resins used for the resin layer described herein, resincuring agents, compounds, curing accelerators, dielectrics, reactioncatalysts, cross-linking agents, polymers, prepregs, skeletal materials,and the like.

Further, the above-described copper foil provided with a carrier orlaminate may be smaller than the resin or prepreg or resin substrate orresin layer when being viewed in a plane.

EXAMPLES

Hereinafter, the present invention will be described in more detailusing Examples of the present invention, but the present invention isnever limited to these Examples in any way.

Examples 1 to 9, 14 to 18, and Comparative Examples 1 to 5

In an electrolytic chamber, a titanium electrolytic drum was disposedand an electrode was disposed around the drum with a giveninterelectrode distance therefrom. Next, electrolysis was performed inthe electrolytic chamber under the following conditions to depositcopper on the surface of the electrolytic drum, and the copper depositedon the surface of the electrolytic drum was peeled off to continuouslyfabricate an electrolytic copper foil having a thickness of 18 μm as acarrier.

Here, the electrolysis conditions for fabricating the carrier are asfollows.

Copper concentration: 30 to 120 g/L

H₂SO₄ concentration: 20 to 120 g/L

Electrolyte temperature: 20 to 80° C.

Current density: 10 to 100 A/dm²

Here, as the electrolytic drum used for forming the above carrier, anelectrolytic drum which had been polished in advance by using thefollowing method was used. In the polishing method, as illustrated inFIG. 5, the polishing belt was contacted to polish the electrolytic drumin the rolling direction (MD direction) while rolling the electrolyticdrum and simultaneously the polishing belt was moved with oscillationalso in the TD direction of the electrolytic drum to thereby polish theelectrolytic drum in the TD direction as well. Here, a titanium drum wasused as the electrolytic drum, and a polishing belt manufactured byHitachi Koki Co., Ltd. (particle size #320 endless polishing belt, typeand particle size of abrasive grain: AA 320 (AA: alumina)) was used asthe polishing belt. The TD direction length of the electrolytic drum was2,400 mm and the width of the polishing belt was 100 mm. The oscillationwidth of the polishing belt in the TD direction, the movement of thepolishing belt in the TD direction (stroke: the number of returns of thecenter of the polishing belt to the same position in the TD direction ofthe electrolytic drum surface within a certain time), the moving speed(carriage speed) of the polishing belt in the TD direction, and therotation speed of the electrolytic drum are shown in Table 1.

Subsequently, a Ni layer having an amount to be deposited of 4,000μg/dm² was formed on the drum surface (glossy surface) side of theabove-described carrier as an intermediate layer by electroplating witha roll-to-roll continuous plating line under the following conditions.

Ni Layer

Nickel sulfate: 250 to 300 g/L

Nickel chloride: 35 to 45 g/L

Nickel acetate: 10 to 20 g/L

Trisodium citrate: 15 to 30 g/L

Gloss agent: Saccharine, butynediol etc.

Sodium dodecyl sulfate: 30 to 100 ppm

pH: 4 to 6

Bath temperature: 50 to 70° C.

Current density: 3 to 15 A/dm²

After the Ni layer surface formed in the above-described conditions hadbeen washed with water and acid, a Cr layer having an amount to bedeposited of 11 μg/dm² was then deposited on the Ni layer with aroll-to-roll continuous plating line by an electrolytic chromatetreatment under the following conditions.

Electrolytic Chromate Treatment

Solution composition: potassium dichromate 1 to 10 g/L, zinc 0 to 5 g/L

pH: 3 to 4

Solution temperature: 50 to 60° C.

Current density: 0.1 to 2.6 A/dm²

Coulomb amount: 0.5 to 30 As/dm²

Example 10 to 13

For Examples 10 to 13, an intermediate layer was formed on the drumsurface (glossy surface) side of the above-described carrier as follows.

Example 10 Intermediate Layer (1) Ni—Mo Layer (Nickel-Molybdenum AlloyPlating)

A Ni—Mo layer having an amount to be deposited of 3,000 μg/dm² wasformed by electroplating a carrier with a roll-to-roll continuousplating line under the following conditions. The specific platingconditions are shown below.

(Solution composition) Ni sulfate hexahydrate: 50 g/dm³, sodiummolybdate dihydrate: 60 g/dm³, sodium citrate: 90 g/dm³

(Solution temperature) 30° C.

(Current density) 1 to 4 A/dm²

(Conduction time) 3 to 25 seconds

Example 11 Intermediate Layer (1) Ni Layer (Nickel Plating)

A Ni layer was formed under the same conditions as in Examples 1 to 9.

(2) Organic Substance Layer (Organic Substance Layer FormationTreatment)

Next, after the Ni layer surface formed in (1) had been washed withwater and acid, an organic substance layer was then formed under thefollowing conditions by showering and spraying the Ni layer surface withan aqueous solution having a solution temperature of 40° C. and a pH of5 that included carboxybenzotriazole (CBTA) in a concentration of 1 to30 g/L for 20 to 120 seconds.

Example 12 Intermediate Layer (1) Co—Mo Layer (Cobalt-Molybdenum AlloyPlating)

A Co—Mo layer having an amount to be deposited of 4,000 μg/dm² wasformed by electroplating a carrier with a roll-to-roll continuousplating line under the following conditions. The specific platingconditions are shown below.

(Solution composition) Co sulfate: 50 g/dm³, sodium molybdate dihydrate:60 g/dm³, sodium citrate: 90 g/dm³

(Solution temperature) 30° C.

(Current density) 1 to 4 A/dm²

(Conduction time) 3 to 25 seconds

Example 13 Intermediate Layer (1) Cr Layer (Chromium Plating)

(Solution composition) CrO₃: 200 to 400 g/L, H₂SO₄: 1.5 to 4 g/L

(pH) 1 to 4

(Solution temperature) 45 to 60° C.

(Current density) 10 to 40 A/dm²

(Conduction time) 1 to 20 seconds

Amount of Cr deposited: 350 μg/dm²

After forming an intermediate layer, an ultrathin copper layer having athickness of 0.8 to 5 μm was formed on the intermediate layer byelectroplating under the following conditions to make a copper foilprovided with a carrier. That is, in an electrolytic chamber, a titaniumelectrolytic drum was disposed and an electrode was disposed around thedrum with a given interelectrode distance therefrom, and electrolysiswas performed under the following conditions to form an ultrathin copperlayer on the intermediate layer side surface of the carrier on which anintermediate layer had been formed.

Ultrathin Copper Layer

Copper concentration: 30 to 120 g/L

H₂SO₄ concentration: 20 to 120 g/L

Electrolyte temperature: 20 to 80° C.

Current density: 10 to 100 A/dm²

In Examples 1, 4, and 7, a roughened layer, a heat resistant-treatedlayer, a chromate layer, and a silane coupling-treated layer werefurther provided above the ultrathin copper layer. In Examples 2, 5, and8, a heat resistant-treated layer, a chromate layer, and a silanecoupling-treated layer were further provided above the ultrathin copperlayer. In Examples 3, 6, and 9, a chromate layer and a silanecoupling-treated layer were further provided above the ultrathin copperlayer.

Roughening Treatment

Cu: 10 to 20 g/L

Co: 1 to 10 g/L

Ni: 1 to 10 g/L

pH: 1 to 4

Temperature: 40 to 50° C.

Current density Dk: 20 to 30 A/dm²

Time: 1 to 5 seconds

Amount of Cu deposited: 15 to 40 mg/dm²

Amount of Co deposited: 100 to 3,000 μg/dm²

Amount of Ni deposited: 100 to 1,000 μg/dm²

Heat Resistant Treatment

Zn: 0 to 20 g/L

Ni: 0 to 5 g/L

pH: 3.5

Temperature: 40° C.

Current density Dk: 0 to 1.7 A/dm²

Time: 1 second

Amount of Zn deposited: 5 to 250 μg/dm²

Amount of Ni deposited: 5 to 300 μg/dm²

Chromate Treatment

K₂Cr₂O₇

(Na₂Cr₂O₇ or CrO₃): 2 to 10 g/L

NaOH or KOH: 10 to 50 g/L

ZnO or ZnSO₄7H₂O: 0.05 to 10 g/L

pH: 7 to 13

Bath temperature: 20 to 80° C.

Current density 0.05 to 5 A/dm²

Time: 5 to 30 seconds

Amount of Cr deposited: 10 to 150 μg/dm²

Silane Coupling Treatment

Vinyltriethoxysilane aqueous solution

(Vinyltriethoxysilane concentration: 0.1 to 1.4 wt %)

pH: 4 to 5

Time: 5 to 30 seconds

Evaluations were performed using the following methods for each of thecopper foils provided with a carrier obtained in Examples andComparative Examples as described above.

Thickness of Ultrathin Copper Layer

The thickness of an ultrathin copper layer of a copper foil providedwith a carrier produced was measured using a gravimetric method.

First, after the weight of a copper foil provided with a carrier wasmeasured, the ultrathin copper layer was peeled off to measure theweight of the obtained carrier, and the difference between the formerand the latter was defined as the weight of the ultrathin copper layer.A 10 cm square sheet stamped out with a press machine was used as anultrathin copper layer piece to be measured. And then, the thickness ofan ultrathin copper layer was calculated using the following formula.

Thickness (μm) of ultrathin copper layer=weight (g) of ultrathin copperlayer/{density of copper (8.94 g/cm³)×area of ultrathin copper layer(100 cm²)}×10⁴ (μm/cm)

An HF-400 manufactured by A&D Company, Limited was used as thegravimeter and an HAP-12 manufactured by Noguchi Press Co., Ltd. wasused as the press machine.

Specular Gloss at 60°

After a copper foil provided with a carrier and a base material(GHPL-832NX-A manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.)were lamination-pressed while heated at 220° C. for 2 hours, the carrierwas peeled off based on JIS C 6471 (1995, the method for peeling off acopper foil was (1) Method A in 8.1.1 Types of Test Method in 8.1 PeelStrength of Copper Foil (a method in which a copper foil is peeled offin a direction with an angle of 90° relative to the copper foil-removingsurface)) to expose the intermediate layer side surface of the ultrathincopper layer. Next, using a Handy Gloss Meter PG-1, a gross meter basedon JIS Z8741 manufactured by NIPPON DENSHOKU INDUSTRIES Co., LTD., thespecular gloss at 60° in the MD direction (rolling direction(longitudinal direction, travelling direction in an apparatus forfabricating a copper foil provided with a carrier)) and the speculargloss at 60° in the TD direction (traverse direction (width direction))of the intermediate layer side surface of the ultrathin copper layerwere each measured at an incident angle of 60°.

Measurement of Surface Roughness (Ten Point Average Roughness Rz)

After a copper foil provided with a carrier and a base material(GHPL-832NX-A manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.)were lamination-pressed while heated at 220° C. for 2 hours, the copperfoil carrier was peeled off based on JIS C 6471 (1995, the method forpeeling off a copper foil was (1) Method A in 8.1.1 Types of Test Methodin 8.1 Peel Strength of Copper Foil (a method in which a copper foil ispeeled off in a direction with an angle of 90° relative to the copperfoil-removing surface)) to expose the intermediate layer side surface ofthe ultrathin copper layer. Next, using the contact roughness meterSurfcorder SE-3C manufactured by Kosaka Laboratory Ltd., the ten pointaverage roughnesses Rz in the MD direction (rolling direction(longitudinal direction, travelling direction in an apparatus forfabricating a copper foil provided with a carrier)) and in the TDdirection (traverse direction (width direction)) of the intermediatelayer side surface of the ultrathin copper layer were each measuredbased on JIS B0601-1982. Under conditions of a measurement referencelength of 0.8 mm, an evaluation length of 4 mm, a cutoff value of 0.25mm, and a conveying speed of 0.1 mm/sec, measurements were eachperformed at 10 different positions in the direction perpendicular tothe travelling direction of an electrolytic copper foil (a copper foilprovided with a carrier) (TD, i.e., width direction) in an apparatus forfabricating an electrolytic copper foil (a copper foil provided with acarrier), and the average value of the 10 measurements was defined asthe value of the surface roughness (ten point average roughness Rz).

Process Capability Index: Cp

In a managed process, the capability of the process to achieve a qualityis referred to as process capability. A larger Cp value as a processcapability index indicates that the variability of holes is smaller thanthe standard and the precision of the size of a laser hole is higher.The process capability index Cp was calculated using the followingformula for each of the samples.

Cp=(USL−LSL)/6σ

USL: upper limit value of standard (laser hole diameter φ60 μm (50+10μm))

LSL: lower limit value of standard (laser hole diameter φ40 μm (50−10μm))

σ: standard deviation of laser hole diameter

Laser Hole-opening Properties

After a copper foil provided with a carrier and a base material(GHPL-832NX-A manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.)were lamination-pressed while heated at 220° C. for 2 hours, the copperfoil carrier was peeled off based on JIS C 6471 (1995, the method forpeeling off a copper foil was (1) Method A in 8.1.1 Types of Test Methodin 8.1 Peel Strength of Copper Foil (a method in which a copper foil ispeeled off in a direction with an angle of 90° relative to the copperfoil-removing surface)) to expose the intermediate layer side surface ofthe ultrathin copper layer. And then, the exposed intermediate layerside surface of the ultrathin copper layer of the copper foil providedwith a carrier was irradiated with one or two laser shots under thefollowing conditions, and the hole shape after the irradiation wasobserved with a microscope to measure. For the “actual number” of holeopenings in Table, hole opening was performed at 150 points and how manyholes could not be opened actually (number of unopened holes) wasobserved. Here, the diameter of a hole was defined as the diameter ofthe smallest circle enclosing the hole.

Gas species: CO₂

Opening diameter of copper foil (targeted): 50 μm in diameter

Beam shape: top hat

Output: 2.40 mJ/10 μs (=240 W)

Pulse width: 33 μs

Number of shots:

1 shot (in the case that the thickness of an ultrathin copper layer is0.8 to 2 μm)

2 shots (in the case that the thickness of an ultrathin copper layer is3 to 5 μm)

The test conditions and the test results are shown in Table 1.

TABLE 1 Carrier Side Surface of Ultrathin Copper Layer After PeelingUltrathin Copper Layer Number Electrolytic Drum Polishing ContactRoughness of Stroke Drum Meter Rz (μm) Gloss (-) Unopened Foil (TraverseCarriage Rotation Rolling Traverse Rolling Traverse CP Holes ThicknessPolishing) Speed Speed Direction Direction MD/ Direction Direction MD/(50 ± (N = 150 (μm) (strokes/min) (cm/min) (rpm) MD TD TD MD TD TD 10μm) holes) Example 1 2 80 20 10 0.99 1.43 0.69 137 61 2.25 0.79 0Example 2 1.5 80 20 10 0.99 1.43 0.69 137 61 2.25 1.01 0 Example 3 0.880 20 10 0.99 1.43 0.69 137 61 2.25 1.33 0 Example 4 2 120 20 10 0.961.52 0.63 134 60 2.23 0.64 1 Example 5 1.5 120 20 10 0.96 1.52 0.63 13460 2.23 1.12 0 Example 6 0.8 120 20 10 0.96 1.52 0.63 134 60 2.23 1.37 0Example 7 2 150 50 7 0.93 1.43 0.65 116 61 1.90 0.95 0 Example 8 1.5 15050 7 0.93 1.43 0.65 116 61 1.90 1.21 0 Exarnple 9 0.8 150 50 7 0.93 1.430.65 116 61 1.90 1.60 0 Example 10 0.8 150 50 7 0.93 1.43 0.65 115 611.89 1.61 0 Exarnple 11 2 150 50 7 0.93 1.43 0.65 116 61 1.90 0.95 0Example 12 1.5 150 50 7 0.93 1.43 0.65 116 61 1.90 1.21 0 Example 13 0.8150 50 7 0.93 1.43 0.65 116 61 1.90 1.60 0 Example 14 2 200 50 5 0.921.42 0.65 81 43 1.88 1.19 0 Example 15 1.5 200 50 5 0.92 1.42 0.65 81 431.88 1.47 0 Example 16 0.8 200 50 5 0.92 1.42 0.65 81 43 1.88 1.98 0Example 17 3 200 50 5 0.92 1.42 0.65 81 43 1.88 1.93 0 Example 18 5 20050 5 0.92 1.42 0.65 81 43 1.88 0.72 1 Comparative 2 0 20 20 0.79 1.520.52 150 70 2.14 0.51 14 Example 1 Comparative 1.5 0 20 20 0.79 1.520.52 150 70 2.14 0.84 4 Example 2 Comparative 0.8 0 20 20 0.79 1.52 0.52150 70 2.14 1.30 0 Example 3 Comparative 3 0 20 20 0.79 1.52 0.52 150 702.14 0.83 5 Example 4 Comparative 5 0 20 20 0.79 1.52 0.52 150 70 2.140.41 18 Example 5

Evaluation Result

In any of Examples 1 to 18, the specular gloss at 60° in an MD directionof the intermediate layer side surface of the ultrathin copper layer was140 or less or the specular gloss at 60° in a TD direction of theintermediate layer side surface of the ultrathin copper layer was 65 orless, and the laser hole-opening properties of the ultrathin copperlayer were good.

In any of Comparative Examples 1 to 5, the specular gloss at 60° in anMD direction of the intermediate layer side surface of the ultrathincopper layer was more than 140 and the specular gloss at 60° in a TDdirection of the intermediate layer side surface of the ultrathin copperlayer was more than 65, and the laser hole-opening properties of theultrathin copper layer were poor.

1. A copper foil provided with a carrier comprising, in order, acarrier, an intermediate layer, and an ultrathin copper layer, whereinat least one of the following (a) and (b) is satisfied: (a) a speculargloss at 60° in a machine direction (MD) of the intermediate layer sidesurface of the ultrathin copper layer is 140 or less; (b) a speculargloss at 60° in a transverse direction (TD) of the intermediate layerside surface of the ultrathin copper layer is 65 or less.
 2. The copperfoil provided with a carrier according to claim 1, wherein a speculargloss at 60° in a machine direction (MD) of the intermediate layer sidesurface is 130 or less.
 3. The copper foil provided with a carrieraccording to claim 2, wherein a specular gloss at 60° in a machinedirection (MD) of the intermediate layer side surface is 120 or less. 4.The copper foil provided with a carrier according to claim 1, wherein aspecular gloss at 60° in a transverse direction (TD) of the intermediatelayer side surface of the ultrathin copper layer is 60 or less.
 5. Thecopper foil provided with a carrier according to claim 1, wherein aspecular gloss at 60° in a transverse direction (TD) of the intermediatelayer side surface of the ultrathin copper layer is 55 or less.
 6. Thecopper foil provided with a carrier according to claim 1, wherein aspecular gloss at 60° in a machine direction (MD) of the intermediatelayer side surface of the ultrathin copper layer/a specular gloss at 60°in a transverse direction (TD) of the intermediate layer side surface ofthe ultrathin copper layer is 2.05 or less.
 7. The copper foil providedwith a carrier according to claim 1 comprising: one or more layersselected from the group consisting of a roughened layer, a heatresistant layer, an anti-corrosion layer, a chromate-treated layer, anda silane coupling-treated layer, in the case that the copper foilprovided with a carrier according to claim 1 comprises an ultrathincopper layer on one side of the carrier, on at least one surface or bothsurfaces on the ultrathin copper layer side and the carrier side; or inthe case that the copper foil provided with a carrier according to claimI comprises an ultrathin copper layer on both sides of the carrier, onone or both surface(s) on the ultrathin copper layer side.
 8. The copperfoil provided with a carrier according to claim 7, wherein the roughenedlayer is a layer consisting of a simple substance selected from thegroup consisting of copper, nickel, cobalt, phosphorous, tungsten,arsenic, molybdenum, chromium, and zinc, or an alloy comprising one ormore thereof.
 9. The copper foil provided with a carrier according toclaim 7 comprising a resin layer provided above one or more layersselected from the group consisting of the roughened layer, the heatresistant layer, an anti-corrosion layer, a chromate-treated layer, anda silane coupling-treated layer.
 10. The copper foil provided with acarrier according to claim 1 comprising a resin layer provided above theultrathin copper layer.
 11. The copper foil provided with a carrieraccording to claim 9, wherein the resin layer is a resin for adhesionand/or a resin in a semi-cured state.
 12. A laminate fabricated using acopper foil provided with a carrier according to claim
 1. 13. A laminatecomprising a copper foil provided with a carrier according to claim 1and a resin, wherein a part or all of an edge face of the copper foilprovided with a carrier is covered with the resin.
 14. A laminate,wherein one copper foil provided with a carrier according to claim 1 islaminated from the carrier side or the ultrathin copper layer side onthe carrier side or the ultrathin copper layer side of another copperfoil provided with a carrier according to claim
 1. 15. A printed wiringboard fabricated using a copper foil provided with a carrier accordingto claim
 1. 11. An electronic device fabricated using a printed wiringboard according to claim
 15. 17. A method for fabricating a printedwiring board comprising: forming a copper-clad laminate by carrying outa step of preparing a copper foil provided with a carrier according toclaim 1 and an insulating substrate, a step of laminating the copperfoil provided with a carrier and the insulating substrate, and a stepof, after the copper foil provided with a carrier and the insulatingsubstrate have been laminated, peeling the carrier of the copper foilprovided with a carrier; and then forming a circuit by any of asemi-additive method, a subtractive method, a partly additive method,and a modified semi-additive method.
 18. A method for fabricating aprinted wiring board comprising: a step of forming a circuit on theultrathin copper layer side surface or the carrier side surface of acopper foil provided with a carrier according to claim 1; a step offorming a resin layer on the ultrathin copper layer side surface or thecarrier side surface of the copper foil provided with a carrier so thatthe circuit is buried; a step of forming a circuit on the resin layer; astep of peeling the carrier or the ultrathin copper layer after formingthe circuit on the resin layer; and a step of exposing the circuitburied in the resin layer that is formed on the ultrathin copper layerside surface or the carrier side surface by, after the carrier or theultrathin copper layer has been peeled off, removing the ultrathincopper layer or the carrier.
 19. A method for fabricating a printedwiring board comprising: a step of laminating the ultrathin copper layerside surface or the carrier side surface of a copper foil provided witha carrier according to claim 1 and a resin substrate; a step ofproviding two layers of a resin layer and a circuit at least one time onthe ultrathin copper layer side surface or the carrier side surface ofthe copper foil provided with a carrier opposite to a side with theresin substrate laminated thereon; and a step of, after the two layersof the resin layer and the circuit have been formed, peeling the carrieror the ultrathin copper layer from the copper foil provided with acarrier.
 20. A method for fabricating a printed wiring board comprising:a step of providing two layers of a resin layer and a circuit at leastone time on one side or both sides of a laminate according to claim 12;and a step of, after the two layers of the resin layer and the circuithave been formed, peeling the carrier or the ultrathin copper layer fromthe copper foil provided with a carrier constituting the laminate.